There is no way that we can answer your questions. It's your job, as a consumer, to do your homework before you bring a plant home so that you are able to provide it with the best possible care from day one.

Only you are able to determine if your plant has been exposed to extremes of one kind or another since it has been with you. It sure sounds as if something is out of whack, doesn't it?

What kind of environment did it have at the nursery? Is it planted in the ground or in a container? If in the ground, was it planted with peat or other amendments in the hole? Do you know what the pH of your soil is does it drain readily after a heavy rain or watering? If in a container, what sort of potting medium did you use? Is the plant situated in full sun?

It was all green in a black plastic container & put inside the nursery house. The nursery owner told me not to plant in the ground until a year or so. She said that I should water it every 8-10 days from Dec to Feb and once a week the rest of the year. Thus, I didn't water it until Monday evening, but watered it a bit again Tue evening since it was hot like 76f. But then found some leave turned red color yesterday evening: ( So, I moved it right away from full sunny place to underneath our house where have some sunshine day time.
Sorry, I just check it now but don't know the pH of the soil, it feels a bit wet but no water is drained after that. Please see the pix(sigh, don't' know how to upload multiple pix) well, it is red on the top of the leave s but green on the back though.

More pics

More pics

{{!gwi}}

That sure looks like sunscald to me. Find a bright location with protection from the hottest afternoon sun.

When you water, it must be done thoroughly. Drench again and again until the excess is draining freely from the bottom. Don't let it sit in water.

I'd advise that you ignore the advice from the nursery owner. Your plant should be watered on an as needed basis, never by the calender. Use your fingers to poke around in the soil. It should feel somewhat dry before watering. Depending on many factors, that could mean every day or several days.

I do wonder why the owner recommended not planting it directly into its permanent location. That seems risky to me, unless you're somewhat experienced at container growing.

Most everything I have and read about scald is that it refers to sun burn of a trees bark. Leaf burn from too much sun and too little moisture is scortch.
However those leaves look like they may have a
phosphorus deficiency.

Here is a link that might be useful: about leaf scortch

OP's original comments said it came from a greenhouse. Putting it outdoors before hardening off is the problem,

So I agree with the opinion that the problem was excess sunlight.

Beyond that, the terms scorch and sunscald are often used interchangeably. Whether or not that matches with the technical description, the key thing to understand is that the underlying problem is excessive light that damaged the cells.

Thank you all for the valuable advice. I watered it thoroughly until some water coming out from bottom. Will these leaves die eventually? Now I move it to a spot where it can get some morning sunshine then will move back later so it won't explore to the direct full sun... But I can do these moves weekends only:( I wonder how soon it can undertake the sunshine the whole day without getting sun scale. Well, by browsing here, one has a big m. Alba in his yard in the same city SF. And, my worker has it plant in the ground since day one in easy bay they got it a good deal at a street fair, I just can't simply wait for a street fair taking place in half year or so. Thus, we drove all the way to the nursery in San Jose ca to buy one. Anyway, can someone tell if it is really unhealthy & will die soon or later?? I just take this pic with the morning sun on it. By the way how to upload more than one pic within a same post?? Thanks again

Update my M A; it has a lot of new leaves now:) hopefully it will have its very first flower soon...

Hi Loveblueroses, my interest on M. alba and champaca began only two months ago. Purchased two little trees online and have been spending way too much time reading posts such as this one. Like you, I'm very fearful of doing the wrong thing to my precious trees :) Anyway, glad to see that your 'red leaf' experience two years ago was just a scare. From the latest pic, you alba looks very good. Q: is the tree still in a pot? Has it started flowering yet? Any experience you can share with a novice would be greatly appreciated. Thanks!

thanks for your inquiry. As you can see it from the picture above, it has been planted in the ground since then. here is the link to another post where you can read my sharing with vr46. http://forums.gardenweb.com/discussions/3036668/michelia-alba-yellow-leaves-repotting-questions Since then, I have seldom watered it since last fall, to conserve water. As a result, it had some dry leaves at some point during the driest, yet. during such it still had only one or two flowers and even a couple "fruits." Other than that, especially with more rain recently, it has been doing well and flowering again. I guess that it should do well, once it has established /grown new roots... hope this can help and good luck too

I just read your other post. Looking good! Thanks for sharing. Congrats on the flowers. I'm so anxious for some flowers that I decided to buy a second (bigger) tree which I did yesterday. Keeping my fingers crossed.